There are a number of variations for Nam Jim, but the key elements of a balanced hot, sour, salty and sweet must always be there. Sometimes in Northeast Thailand the fifth taste element of bitter is added as well.
Making Nam Jin is a great way to learn of the balance of Thai-taste basics of hot, sweet, sour, and salty using the key ingredients of chiles, garlic, fish sauce, lime juice and date palm sugar. Add and subtract as much as you like, taste, adjust to your palate and keep adding to the perfect balanced flavour.
Some people are sensitive to the heat of chiles and can balance to less chile heat or garlic. Also you can use milder chiles and adjust accordingly.
Nam Pla or Thai fish sauce is a vital ingredient in all Thai cooking. Don't be put off by the "fishy" smell. Once the fish sauce is added to a dish it combines and creates a lovely taste not a strong fishyness at all. It is key to buy good quality fish sauce. I prefer the ones that are naturally made without the chemicals. Golden Boy (label as a fat little happy boy sitting) is my favourite brand, but I also like Tra Chang (label has a weighing scale on it).
Fish Sauce to Southeast Asians is much like soy sauce for Chinese and Japanese as an ingredient to provide a saltiness to a recipe. Fish sauce becomes addictive to your palate and Thai dishes just aren't right if it is missing.
Fish sauce is made from fermented anchovies or sometimes shrimp.
1/4 cup fish sauce
6 tablespoons freshly squeezed lime juice
4-5 garlic cloves
3-4 tablespoons palm sugar
4 red shallots minced
3-8 birdís eye chiles (to taste)Thai Dragons or Serranos can be used
1/4 cup chopped cilantro leaves or 1 fresh cilantro root (best flavour!)
Pinch of salt
In a large mortar, crush the garlic with the salt, add the cilantro and chiles using the pestle and roughly pound. Stir in the sugar, fish sauce, lime juice and finely minced shallots.
Cilantro root can be hard to find, but ask at your farmer's market or Asian market if they have the cilantro with the roots. The roots impart an amazing taste. I grow my own so I have these fragrant and wonderful roots for my curry pastes.
Date Palm Sugar - you can subsitute brown sugar if date palm sugar is unavailable. Don't use white sugar as it has a far too sharp sweetness for balancing the flavours. White sugar is often used in Western Thai restaurants to cut the heat of the chiles, but it destroys the important balance of hot, sweet, salty, sour which is the heart of Thai cuisine.